The disclosed subject matter is in the field of transparent conductive coatings for display and touch screen applications.
Indium tin oxide (ITO) coatings on polyester films (like PET) are commercially available and face a major technical hurdle in their implementation with flexible display applications due to the poor mechanical strength of the ITO film and its rapid mechanical failure on flexing.
On the other hand carbon nanotube (CNTs) based films have been gaining importance in recent times as potential replacement for ITO in transparent conductive applications. The major advantage of carbon nanotubes is their electrical conductance, even in the form of a few nanometers thick film, coupled with their extreme mechanical flexibility. Since robust CNT films can be made at extremely small thicknesses, e.g., a CNT monolayer, the resulting films can be transparent and conductive. However, dense CNT networks cannot be made except with a loss in the optical transparencies because CNTs are intrinsically light absorbing in the visible and UV regions.
Depositing a single dispersion of transparent conductive oxide particles with carbon nanotubes have been proposed. However, realization of such methodology is thought to be extremely difficult due to flocculation of the various species during dispersion formation and/or during coating.
Laminates of transparent conductive oxide layers with carbon nanotubes layers have also been proposed. However, such structure nevertheless suffers from the respective problems associated with the single carbon nanotube (e.g., poor optical transparencies) and single transparent conductive oxide films (e.g., poor mechanical strengths) noted above.